Insulated connecter for outlet boxes



y 1932- H. G. KNODERER 1,857,197

I INSULATED CONNECTER FOR OUTLET BOXES Filed Jan. 26, 1929 In Ventor I WH is fltt orney.

Hom e21" G. Kn cleren' Patented May 10, 1932 UNITED STATES PATENT OFFICEHOMER G. KNODERER, OF FAIRFIELD, CONNECTICUT, ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK INSULATED GONNEGTER FOROUTLET BOXES Application filed January 26, 1929. Serial No. 335,35'7.

My invention'relates to an improved combination of elements ;of utilityin connection with armored conductors, such as are em ployed in housewiring and the like and more 15" particularly to an improved insulatingbushing and connecter combination for securing armored conductors tooutlet boxes and the like. An object of my invention is to provide anarrangement of parts which will insure that the insulated wires ofarmored conductors are protected from the sharp end edges of the armorwithout the necessity for particular thought or care on the part of theworkman in making-the installation.

A further object of my invention is to provide a combination ofinsulating bushing and connecter which will also protect the conductorsfrom any sharp edges on the part of the connecter, which extends intothe outlet box, so that the conductor insulation will not be injuredthereby.

A further object of my invention is to provide a construction which willpermit conmeters and insulating bushings to be readily assembled andenable the combined connecter and bushing to be shipped and sold as aunit and handled by the workman as a unit when making an installation.

A further object of my invention is to provide an arrangement which whenthe installation is completed will enable an inspector readily todetermine whether or not the installation has been properly made.

A further object of my invention is to prov vide a simple and ruggedarrangement of parts which makes it impossible for the bushing to beremoved from the connecter after the armor stripped ends of theconductors are inserted into the bushing and whichpermits the workman toforce the armored conductor into position for clamping without danger offorcing out the bushing, and which will insure that the conductors areprotected from the sharp end edges of the armor when the armor has beenpushed into the connecter far enough to permit it to'be secured thereinby the clamping means thereof.

While my invention is particularly useful in connection with armoredconductors, it is also advantageous for use in connection with flexiblemetallic conduit which is secured by connecters in a similar way tooutlet boxes and the like and into which conduit the conductors aredrawn and the electrical connections made after the conduit system hasbeen installed. In such an arrangement my invention protects theconductors from injury by the sharp edges on the conduit and connecterand also provides a smooth uninter rupted runway for the drawn in wires.

My invention will be better understood when considered in connectionwith the following specification and accompanying drawings and its scopewill be pointed out in the appended claims.

Referring to the drawings, Fig. 1 is a side elevation, with part brokenaway, of an ar mored conductor with the right-hand end stripped ofarmor; Fig. 2 is an axial section of the connecter with my insulatingbushing in place; Fig. 3 are sections of a junction box wall andconnecter retaining nut; Fig. 4 is a perspective view of the outerend ofthe connecter; Fig. 5 is an assembled view of the several parts shown inFigs. 1, 2 and 3; Fig. 6 is a side elevation of another form of armoredconductor showing the sharp end edge customarily formed in the cuttingof the armor to bare or strip the ends of the insulated wires; Fig. 7 isa part side elevation and part section of a flexible metallic conduitassembled in a connecter provided withmy insulating bushing; Fig. 8 is aperspective view with part broken away of the inner end of a difierentform of connecter and insulating bushing; Fig. 9 is a similar view ofanother form of connecter and insulating bushing; Fig. 10 is a View ofthe application of my invention with a different form of clamping meansand Fig. ll represents a modified construction of insulating bushing.

As is well known, the armor of armored conductors and the flexiblemetallic conduits of commerce are composed of continuous metal strips orribbons profiled in cross section and coiled helically so that the edgesthereof become interlocked with a certain amount of freedom-to slip uponeach other when the finished article is bent. It is customary in 105installing armored conductors and flexible metallic conduit to cut theprofiled metallic strip by suitable means such as a hack saw. Thisusually leaves a sharp projecting end edge or corner which is apt topenetrate the insulation of the conductors. Also, unless special care istaken by the wireman, the hack saw may cut. into or through theinsulation of the wires of armored conductors di: rectly beneath thesharp end edge thereby increasing the liability of an electrical contactbetween the armor and the wires. After a portion of the armor has thusbeen severed and removed, the armored conductor is secured by suitablemeans such as a connecter to the. outlet box into which the wiresproject. The manipulation of these wires by the wireman in makingconnections is likely further to injure the insulation on the wires byreason of sharp edges or projections on the armor or the connecter.

In accordance with my invention I provide an improved insulating bushingwhich projects between the wires and the armor of the armored conductorto form an insulating and protecting sleeve to protect the wires frominjury by sharp edges or projections on the armor and which bushes theend of the connecter which extends into the outlet box to protect thewires against injury from theconnecter. Referring to Figs. 2 and 5 itwill be seen that the bushing 4 is mounted in the connecter 8. As willbe more particularly set forth hereafter, the bushing is constructed sothat when it has been inserted into the connecter it will be securelyretained in the connecter and the bushing and connecter may be handledas a unit. After a portion of the armor of the armored conductor hasbeen removed the projecting wires are inserted through the connecter andbushing as above described. In Fig. 1 the projecting wires of thearmored conductor are shown at 2 and the armor at 3. In order to enablethe bushing to be readily inserted between the wires and the armor, Iprefer to use an armored conductor which is provided with a wrapping 1which may be ofpaper. After the armor has been cut and a portion removedso as to leave the projecting wires a portion of the paper wrapping 1may be pulled out and the wrapping severed for a distance back into thear mor sufficient to accommodate the sleeve of the bushing which.projects between the wires and the armor. While I at present prefer touse armored conductors with such a wrapping my invention is alsoapplicable to other forms of armored conductors where there is a smallamount of looseness or space between the conductors 2 and the armor 3which permits the bushing to be forced into place.

I prefer to make the insulating bushing 4 in the form of a split tube offiber or other suitable resilient insulating material provided at theinner or outlet box end with two spaced shoulders, one of which is anend flange 5 and the other a bead 6 between which shoulders the inturnedflange or contracted part 7 of the connecter 8 is located when thebushing is in place in the connector. l/Vhen the bushing is forced intothe shouldered or contracted part 7 of the connecter 8 the head 6 snapsthrough the contracted part 7 and the latter is then embraced onopposite sides by the spaced shoulders of parts 5 and 6 and servesthereby to hold the insulating bushing definitely positioned thereinwith an annular clearance space 9 between the main bore 10 of theconnecter 8 and the outside of the main tubular portion of the bushing.This clearance space 9 is open at its outer end and closed at its inner,as shown in Fig. 2.

In order to facilitate the entrance of the split insulating bushing 4into the space between the insulated conductor-s2 and the inner surfaceof the armor 3, the outer corners 15 thereof adjacent the split arepreferably rounded oil", as shown in Fig. 2, and the outer end of thebushing is preferably made slightly beveled or tapering.

I preferably construct the bushing so that when it is snapped into placein the connecter the longitudinal edges adjacent the split of thebushing come into abutting relation with each other. This serves toresist the collapse of the bushing and provides a complete insulatingsleeve. It is within the scope of my invention, however, to make theslit in the bushing sufficiently wide so that when it is contracted toinsert it in the connecter the edges come into abutting relation andwhen the bushing comes into place its resiliency causes it to be heldfirmly in place. The flange 5 and the bead 6 on the bushing contributeto the resilient action of the bushing.

lVhen the conductors 2 have been inserted through the bushing thecollapse of the bushing is prevented so that the workman may grasp theconnecter 8 in his hand and apply force to drive the sleeve into placebetween the armor and the wires and to drive the connecter 8 over thearmor 3 without danger of. pushing the bushing out of the connecter.

The particular form of connecter 8 shown in section in Figs. 2 and 5 isshown in perspective in Fig. 4. I provide such alength of bushing 4 withrespect to the connecter 8 that when the armor 3 has been forced intothe connecter far enough to enable the armored conductor to be fastenedinto the connecter by tightening the screw 12 the sleeve of the bush-.ing will have been forced between the wires and the armor to thenecessary distance to protect the wires from the sharp edges of thearmor. In other words when the armored conductor has been inserted intothe connecter far enough to enable it to be secured by the clampingmeans it necessarily follows that the bushing is properly located. Afterthe Em cte h been clamped to the armor the tmgaded and of the connecter8 is entered through the/hole in the outlet box wall 13, or otheigwallthrough which the wires are to e led, and the connecter is secured tothe wall y d m Fig. 5.

bushing 4 pro ects over and protects the wires from injury f w 7. Itwill also be observed that the flange 5 of the bushing is in a positionwhere itmay be readily seen by looking into the outlet box. If,therefore, an armor is properly clamped in the connccter and observesthe flange 5 of the bushing, he knows at once that the insulatingbushing is in place and that the job has been properly done. This is afeature of considerable importance since if the bushing were inside 0the'contracted portion 7 of the connecter-rit would be practicallyimpossible for the inspector to determine whether or not the bushing waspresent without disassembling the connection. Even should the inspectordisassemble a few connections in a building and find that the bushingswere in place he woul even then not be sure that the bushings were inplace in the other connections unless he disassembled all of them. ithmy arrangement no disassembling at all is necessary an the inspectioncan be made quickly and with certainty. oreover since the bushing may beshipped in place in the connecter and h dled as a unit by the wiremanthe wireman does not need to exercise the thought and care which wouldbe necessary if separate bushings d which he would have to remember toinsert between the wires and the armor bea the armor in the connecter.will be observed that the sleeve of the bush ing projects within theconnecter and is protected by the connecter so' that it will not bedamaged by the handling and boxing and shipment of the assembled unitscomprising the connecters and bushings.

Fig. 6 represents another orm of armored omits the wrapping 1 o thearmored conductor shown in ig.

This figure also indicates at 11 the sharp corner which customarilyresults when the armor is out with a hack saw as heretofore described.

While my invention is of particular utility in connection witharmoredconductors, it may also be advantageously used with flexible metallicconduits into which the wires are drawn after the conduit installationhas been made. Fig. 7 shows such an application of m invention. 0lt-will be apparent to those skilled art that my invention is notlimited to any one particular type of connecter. Fig. 8 illustratesanothertype of well known conbushing inserted therein.

necter with. .my Fig.9 illustrates still another type of wellin the 1.tween which is known connecter. Fig. 10 illustrates a modifiedarrangement or clamping armore conductors in an outlet box. In this casethe member 16 is mounted inside the outlet box and when the screwpassing through the hole 17 is forced down the member 16 is tilted andclamps the armor 3 in the box. With this type of clamp my bushing a mayalso be used and shipped with the clamping member as a unit. It willthus be seen that my improved arrangement is applicable to manydifferent kinds and types of connecters.

While I at present prefer to use a bushing which is split throughout itslength it is apparent that it is within the scope of my invention to usea bushing which is split or cut through a portion only 0 its length, asindicated in Fig. 11, the split portion being at the end upon which theshoulders 5 an are provide Such a bushing may be either into theconnecter from the end opposite the restricted portion or may beinserted from the restricted end of the bushing if the bushing issuitably tapered, as indicated in Fig. 11, so that the uncut portionwill pass through the restricted portion of the connecter.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. The combination with an armore electrical conductor and an outletbox, of a connecter provided with means for securing it to the armoredconductor and to the outlet box and an insulating bushing comprising asplit cylindrical sleeve located the armor and conductors and providedwithmeans for attaching it to said connector the parts being d so thatwhen the securing means is operative to connect the armored conductor tothe connector the bushing will be located properly to protect andinsulate the conductors from the armor and connecter.

2. The combination with an insulator shield comprising a split tubularbody, one end portion ofwhich is fashioned to form spaced, outwardly andradially projecting members hean annular recess, of a tubular metallicbody, one end portion of which is proinwardly extending flange videdwith an adapted to seat in the recess of said shield to retain the tubeagainst displacement from the shield.

3. The combination with a tubular body having an inwardly and radiallydirecte wall, of a shield of insulating material arranged in the bore ofsaid body, and means on said shield adapted to be arrange sides of saidwall for retaining said sh against displacement from said body.

4:. In combination with an insulated electric conductor and a sheathingtherefor, said conductor having an end portion projecting outwardly froman end of said sheathing, of a coupling adapted to connectsaid conductorield atopposite ill and its sheathing to an electrical fixture, saidmeans provided on said bod d da t d coupling comprising, a tubular bodyadapted to grip said sheathing to retain said oupling to e passed overthe end of said sheathing thereon. and having a substantiallylongitudinally ex- 9. A coupling for armored cables coin r 5 tendingshield member therewithin adapted ing, a tubular body having a sheathinre- 70 to pro ect into said sheathing in surrounding CGIVIHO I andprotecting relation with said insulated 0 an armored cable and asubstantially cyo I n a 4 o a o The combination with a connectorhaviortion extendin lon itudiiiall within said ing a conductor passagewaof a split cylinaperture and concentric therewith for inser- 75 dricalinsulating bushing having means theretion under the cable sheathing, andan attachon for retaining the same against accidental ing flange formedon said bod portion and displacement from Within the passageway ofattached to said tubular body.

tie said connecter so' as to constitute a unit 10. n combination with anarmored cable part thereof, the walls of the split portion at comprisingan insulated electric conductor 80 tric conductor and a sheath therefor,sa d contially cylindrical split shield member having 8 couplingcomprising a tubular body adapted ody portion having a tapered end tofacili- 90 mg and protecting relation with said insulata sheathingreceiving aperture for receiving 95 tric conductor and a sheathingtherefor, said therewith, and an attach n flange formed on 100 couplingcomprising, a tubular b dy adapted n witness whereof, I have hereuntoset my 105 said tubular body, said shield member being 110 plane at anangle to the longitudinal axis of mg, a tubular body having a sheathingresaid bushing. ceiving aperture for receiving the end por- 6. Incombination with aninsulated election 0 said, armored cable and asubstanductor having an end portion projecting outa body portionextending longitudinally withvvardly from an end of said sheathing, of ain said aperture and concentric therewith, and coupling adapted toconnect said conductor an attaching flange formed on said body porandits sheathing to an electrical fixture, said tion and attached to saidtubular body, said to 'e passed over the end of said sheathing tate theinsertion of said body portion under and having a substantiallylongitudinally eX- the cable sheathin q. tending cylindrical splitshield member adapt4 11. In combination with an armored cable of ed toproject into said sheathing in surrounda coupling comprising, a tubularbody having ed conductor, and an attaching flange formed the end portionof said armored cable and on said shield member and attached to said asubstantially cylindrical split shield memtubular body. er having a bodyportion extending longi- In combination with an insulated elec-'tudinally within said aperture and concentric conductor having an endportion projecting said body portion and atta ched to said tubuoutwardlyfrom an end of said sheathing, of a lar body, said body portion having atapered coupling adapted to connect said conductor end to facilitate theinsertion of said body and its sheathing to an electrical fixture, saidportion under the cable sheathing.

to be passed over the end of said sheathing hand this 23rd day of January, 1929.

and having a substantially longitudinally ex- HOMER G. KN ODERER.tending cylindrical shield member therewithin in spaced relation fromthe inner walls of adapted to pro ect under said sheathing and conductorand a sheathing-therefor, said 0011- coupling comprising, a tubular bodyadapted i to be passed over the end of said sheathing I prising asubstantially cylindrical bod portion adapted to surround said insulatedconc uctoi and to project under the end portion of said sheathing toprotect. said insulated conductor from the abrasive action of'said endportion, said shield member having an outwardly extending annular flangefixedly attached to said tubular body, and clamping

